Solar PV on new homes

Marley solar panels on a domestic housing development

Following the long-awaited announcement from the Government about the Future Homes Standard and interim changes to Part L, many housebuilders will be exploring measures and specifications to assess the most effective way to achieve the carbon reduction demands. The announcement that the Government has gone for the tougher option 2, means simple improvements to the building fabric are no longer enough and it will require either solar PV, with a gas boiler, or a heat pump to achieve the required levels.

Clearly each system has its benefits and in the long run, under the Future Homes Standard 2025, it is anticipated that all new homes will have heat pumps as the primary heating system.  To meet the interim 31% reduction though, housebuilders will be looking for the simplest and most cost-effective method, which is why we expect solar PV and efficient gas boilers to be the favoured specification in the short term.  This is because PV technology is already tried and tested, readily available and has become much more affordable.Many housebuilders will also already have a supply chain and trusted installers in place for solar PV roofing.  

While there is clearly a strong will among housebuilders to move towards heat pumps, the availability of installers and an underdeveloped supply chain could be a barrier to theirwider use over the next few years.  In fact, the Environmental Audit Committee recently warned that the supply chain for electric heating solutions, like heat pumps, will be insufficient to meet the government deployment targets.

You only have to look at the experiences of housebuilders in Scotland, where they have had tighter energy efficiency regulations in place since 2015.  As well as some issues with customers accepting heat pumps, the high demand for installers and pumps led to an increase in the cost of installation.  Therefore, most housebuilders in Scotland have opted for the solar PV plus gas boiler option.  

It is also important to consider the fact that, on average, the cost of electricity is roughly four times more expensive than gas.  Indeed, integrated solar manufacturer, Viridian Solar has carried out some modelling which suggested that gas, plus solar PV, resulted in significantly lower energy bills for residents than a heat pump alone.  The Government’s figures back this up, showing that annual energy bills for an efficient gas boiler, plus solar, would be £168 per year v £369 a year for a heat pump.

Housebuilders clearly don’t want complaints from buyers about higher-than-expected energy bills but for them, the initial capital cost is also a bigconcern.  While the Government says that a heat pump package has a lower capital cost than gas boiler plus solar PV, Viridian Solar has found that the costs that were assumed for solar PV were already out of date and will be further out of date by 2022. In fact, the cost of solar technology has decreased by around 80% in the last decade.

So what happens beyond 2025? The draft Future Homes Building Specification, produced by the Government, at this stage includes a heat pump and high levels of fabric efficiency.  This will go out for further consultation and we believe the Government will have to add solar PV.  Heat pumps and solar PV should go hand in hand.  Heat pumps require electricity to run and solar PV can provide this for free, so it would be foolish to ignore it.  By just installing a heat pump, the cost to run the heating and hot water is higher than for gas heating, and with the increasing requirement to charge electric vehicles as well, on-site electricity generation is the way to keep running costs under control for buyers of new homes.  The whole energy market is changing and balancing the grid will become even more important, as more and more electric vehicles come online.

In the past, housebuilders may have had some challenges with solar PV when it came to aesthetics and planning, but the latest innovations mean this is no longer an issue.  New integrated systems, like Marley SolarTile®, simply replace a section of the tiles or slates and become a seamless part of the roof design.  They don’t need specialist contractors and are quick and easy to install.  They can also be purchased as part of our full roof system, so housebuilders can specify the entire pitched roof from one manufacturer, guaranteeing compliance with British Standards, backed up with a 15-year warranty. 

Now only around 10% of new homes in England are built with solar PV, compared to around 80% in Scotland.  We believe that in future this will become as standard as a fitted kitchen – something that homebuyers expect, alongside an EV charging point, solar storage and intelligent whole house heating / energy systems.